This invention concerns delivery of intravenous (IV) solutions to a patient, and is particularly concerned with an infusion pump which applies pressure to a solution bag, which may be a large solution bag, for delivering solution under pressure through tubing to a patient. A portable such infusion pump is a preferred embodiment of the invention.
The subject matter of this invention is related to U.S. Pat. No. 5,681,284, commonly owned with this invention, as well as U.S. Pat. Nos. 4,741,736, 5,330,431 and 5,348,539. As discussed in that patent, infusion pumps are used to deliver various types of solutions intravenously to patients. A variety of drugs are commonly administered to patients by means of intravenous solutions. Among the types of therapies requiring this kind of administration are chemotherapy, antibiotic therapy and antiviral therapy. In many cases, patients receive multiple daily therapies. Certain medical conditions require infusion of drugs in solution over relatively short periods of time, such as from 30 minutes to 2 hours. Infusion pumps have been developed in the prior art in an effort to meet these needs. There has been a requirement of providing portable infusion pumps for use in ambulances and other emergency situations, and by ambulatory patients.
Different types of infusion pumps in the prior art include elastomeric pumps which squeeze the solution from flexible containers, such as bags or balloons, into IV tubing for delivery to the patient. Spring-loaded pumps have also been provided to pressurize the solution containers or reservoirs. In certain infusion pump designs, cartridges containing flexible compound compartments that are squeezed by pressure rollers for discharging the solutions are provided, such as in U.S. Pat. No. 4,741,736. U.S. Pat. No. 5,330,431, issued to the inventor of the present invention, shows an infusion pump in which standard prefilled single dosage IV bags are squeezed by the use of a roller. U.S. Pat. No. 5,348,539, also issued to the inventor of the present invention, shows an infusion pump in which prepackaged IV bags are squeezed by a bladder which is actuated by a fluid pump from a reservoir.
Dispensing spikes have been provided for interconnecting IV tubing with the IV bags. The spikes penetrate through dispensing ports in the bags to permit the fluid to infuse through the tubing to the patient. U.S. Pat. No. 5,106,374 to Apperson discloses a spike having a locating flange which assists in locating the spike within the housing of an ambulatory infusion device.
The prior art infusion devices include arrangements for sensing the pressure of the IV bags to control the infusion procedure, such as for shutting off the infusion flow.
A portable infusion pump of the '284 patent controls the infusion process by indirectly sensing IV solution pressure without intrusion into the bag itself. Also that infusion pump provides a safe and reliable arrangement for sensing when the IV bag is in its proper solution-dispensing position within the compartment of the pump housing and ensures that the dispensing spike cannot be accidentally withdrawn from the bag's dispensing port when the infusion is in progress.
There is a need for an IV infusion pump, particularly a portable infusion pump, which can dispense solution from larger one liter solution bags particularly for emergency situations, and which has versatility and redundancy in operation so as to have alternative pressure sources for situations when needed. In addition, a universal such implement is needed, to receive IV, solution bags from different manufacturers, having two or three different port positions. Further, there is often a need for quick venting of the infusion pump's bladder that puts pressure on the IV bag, so that a new IV bag can be quickly installed.